Methods and nodes for setting values of system parameters used in a wireless communication system

ABSTRACT

Method in a user equipment, a user equipment, a method in a base station and a base station for setting values of system parameters used within a wireless communication system. A first set of parameter values and an associated first tag is sent from the base station to be received and stored by the user equipment. Further, a second set of parameter values and an associated second tag is sent from the base station to be received and stored by the user equipment. When the base station determines to change system information parameters, a command tag is sent, to be received by the user equipment, which apply the set of parameter values associated with the tag corresponding to the received command tag.

TECHNICAL FIELD

The present disclosure relates in general to a method in a userequipment, a user equipment, a method in a base station and a basestation. In particular, it relates to setting values of systemparameters used within a wireless communication system.

BACKGROUND

User equipment (UE), also known as mobile terminals, wireless terminalsand/or mobile stations are enabled to communicate wirelessly in awireless communication system, sometimes also referred to as a cellularradio system. The communication may be made e.g. between two userequipment units, between a user equipment and a regular telephone and/orbetween a user equipment and a server via a Radio Access Network (RAN)and possibly one or more core networks.

The user equipment may further be referred to as mobile telephones,cellular telephones, laptops with wireless capability. The userequipment in the present context may be, for example, portable,pocket-storable, hand-held, computer-comprised, or vehicle-mountedmobile devices, enabled to communicate voice and/or data, via the radioaccess network, with another entity, such as another user equipment or aserver.

The wireless communication system covers a geographical area which isdivided into cell areas, with each cell area being served by a basestation, e.g. a Radio Base Station (RBS), which in some networks may bereferred to as “eNB”, “eNodeB”, “NodeB” or “B node”, depending on thetechnology and terminology used. The base stations may be of differentclasses such as e.g. macro eNodeB, home eNodeB or pico base station,based on transmission power and thereby also cell size. A cell is thegeographical area where radio coverage is provided by the base stationat a base station site. One base station, situated on the base stationsite, may serve one or several cells. The base stations communicate overthe air interface operating on radio frequencies with the mobilestations within range of the base stations.

In 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE),base stations, which may be referred to as eNodeBs or even eNBs, may beconnected to a gateway e.g. a radio access gateway. The radio networkcontrollers may be connected to one or more core networks.

Universal Mobile Telecommunications System (UMTS) is a third generationmobile communication system, which evolved from the GSM. GSM is anabbreviation for Global System for Mobile Communications (originally:Groupe Special Mobile). UMTS is intended to provide improved mobilecommunication services based on Wideband Code Division Multiple Access(WCDMA) access technology. UMTS Terrestrial Radio Access Network (UTRAN)is essentially a radio access network using wideband code divisionmultiple access for mobile stations. The 3GPP has undertaken to evolvefurther the UTRAN and GSM based radio access network technologies.

In 3GPP, the standardization of the Long Term Evolution (LTE) Release 10of UTRAN is currently on-going. The new radio access network may also bereferred to by the acronym E-UTRAN, Evolved UTRAN.

The Radio Resource Control (RRC) protocol is the signalling protocolresponsible for configuring and re-configuring lower layers of the userequipment. These lower layers include the physical layer, Medium AccessControl (MAC), Radio Link Control Protocol (RLC), and Packet DataConvergence Protocol (PDCP). The RRC protocol is terminated in the basestation and the user equipment, respectively.

One important function of the RRC protocol is to distribute SystemInformation. System Information parameter values are distributed fromthe base station to all user equipment units in the entire cell. SystemInformation is used to configure parameters that are needed by the wholeuser equipment population, and parameters in System Information arerelevant for both Idle and Connected user equipment units. Typically,System Information may be used for distributing information about thecarrier, configuration describing common channels and Random Accessparameters, and parameters defining how the user equipment may select orprioritize cells, frequencies and Radio Access Technologies (RATs).Also, the Time Division Duplex (TDD) configuration, describing which ofthe sub frames are for uplink and which are for downlink as well asparameters related to a special sub frame in Time Division LTE (TD-LTE),such as the guard period, may be signalled using System Information.

TDD is an application of time-division multiplexing to separate uplinkand downlink frames in time, possibly with a guard period situated inthe time domain between the uplink and downlink frames.

In the present context, the expression downlink is used for thetransmission path from the base station to the user equipment. Theexpression uplink is used for the transmission path in the oppositedirection i.e. from the user equipment to the base station.

Parameters for system information distribution are grouped into SystemInformation Blocks (SIBs). Currently, there are fourteen such blocksdefined in LTE RRC; a Master Information Block (MIB) and thirteen otherSIBs. MIB contains the most essential information of the cell. This MIBis transmitted in a separate System Information Message, which in thepresent context is referred to as SI-M, that has a fixed time andresource position. SIB1 is also transmitted in separate SystemInformation message 1 (SI-1) and comprises, among other things,information of how other SIBs are mapped into system informationmessages, and how these system information messages are scheduled. SIB1has a fixed periodicity such as e.g. 80 milliseconds, with repetitionse.g. every 20 millisecond and position in the time domain (subframe #5every 2^(nd) radio frame), but the resources are scheduled with PhysicalDownlink Control Channel (PDCCH).

Other SIBs (except MIB and SIB1) that need to be transmitted with thesame periodicity may be mapped into the same System Information message.These System Information messages are dynamically scheduled by regularindications on the PDCCH control channel. A special identity, SystemInformation-Radio Network Temporary Identifier (SI-RNTI), has beendefined to identify scheduling of System Information messages from othertraffic on Downlink Shared Channel (DL-SCH). A single SI-RNTI is usedfor scheduling of all System Information messages on Broadcast ControlChannel (BCCH).

Not all SIBs are transmitted in every cell. For example, SIB8 containsparameters for inter-working with Code Division Multiple Access 2000(CDMA2000), and SIB8 is therefore only transmitted in areas and byoperators where such inter-working is relevant.

MIB, SIB1 and SIB2 must be present in every cell, and this group ofinformation is therefore denoted “essential system information” in LTERRC. A user equipment considers the cell as “barred” in case it cannotfind this essential system information.

System Information Messages are sent periodically, where the mostfrequently needed parameter values may be repeated e.g. every 80millisecond, while parameter values relevant for accessing the cell,such as e.g. random access parameters could be distributed e.g. every160 milliseconds. Cell-selection parameters may be repeated with aperiod of e.g. 320 milliseconds. MIB is per definition scheduled every40 millisecond.

System Information Change

In some cases, there may be a need to update some system informationparameters. For this purpose, a method for system information update hasbeen defined; wherein user equipment units are notified of the changeand may re-acquire the updated system information.

The notification used to indicate that system information change willhappen, must reach both connected (RRC_CONNECTED) and idle (RRC_IDLE)mode user equipment units. This is realized by the use of a“modification period”. System information is changed at the boundary ofmodification period. The length of the modification period defined as:modification period=modificationPeriodCoeff*defaultPagingCycle,where parameter modificationPeriodCoeff has minimum value of 2 anddefaultPagingCycle has minimum value of 32 radio frames. Thus, theshortest possible modification period is 640 milliseconds. Much longerchange periods may also be configured, depending e.g. on the desiredpaging cycle, as may be seen from the equation above.

The parameters defining the modification period are also broadcasted inthe cell, in SIB2.

There are two mechanisms to notify the user equipment units of anupcoming system information change. During the modification period priorto the change, user equipment units in IDLE state are reached by meansof paging, where paging message comprises an indication that systeminformation may change at the end of modification period.

In addition, SIB1 includes a ValueTag of 5 bits that shall be changedfor each change of system information. This value tag shall be changedat the modification border, such that the new system information isassociated with a new value in the ValueTag. Thus, a user equipment thatidentifies a new value on the tag, e.g. after returning fromout-of-coverage, will therefore know whether its stored systeminformation is still valid or not. Stored information whose validity hasnot been verified for 3 hours is considered invalid in the userequipment.

User equipment units in idle mode are required to monitor the pagingchannel. A detection of a system information change indication in apaging message will guide the user equipment to re-read systeminformation starting at the next modification border. A user equipmentin idle mode that has missed some or all its paging opportunities mustverify the validity of system information from the aforementionedValueTag. A user equipment in connected mode may check either paging orthe ValueTag at the modification border to verify the validity of itsstored system information.

These general principles are illustrated in FIG. 1A, in which differentpatterns on the blocks representing system information messages indicatedifferent system information content. Upon receiving a changenotification, the user equipment knows that the current systeminformation is valid until the next modification period boundary. Afterthis boundary, the user equipment acquires the new system information.There is a period during which the user equipment does not have validsystem information. However, the user equipment is allowed to operatewith the “old” system information until it has successfully received theupdated information.

LTE TDD and the Parameters of TDD in SI

LTE may operate both in Frequency Division Duplex (FDD) or TDD mode. Akey difference between TDD and FDD is that for TDD, the same spectrum isshared between uplink and downlink by means of time division. For LTETDD, this means that the ten 1 millisecond sub frames of a 10millisecond radio frame are allocated to uplink or downlink, with the socalled special sub frames. A special sub frame has duration of 1millisecond, and it comprises a Downlink part (DwPTS), a Guard Period(GP) as well as an Uplink part (UpPTS). This is shown in FIG. 1B.

The guard period is utilized to separate uplink and downlink in the userequipment units and the base stations in the presence of propagationdelays, and also for allowing the involved user equipment units and thebase stations to switch between receiving and transmitting mode. Theguard period is typically chosen to match the largest round trippropagation delay in the cell plus the switching time between receivingand transmitting mode of the nodes in the system. The size of the guardperiod may also be chosen to avoid interference from remote basestations which due to propagation delays are still in the air when theuplink begins, despite the fact that all base stations have ceasedtransmission at the same time in a synchronized network.

There are currently seven uplink-downlink configurations and nineconfigurations of the special sub frames. The configurations areillustrated in FIG. 1C and FIG. 1D.

For LTE TDD, the uplink/downlink as well as special sub frameconfigurations are transmitted in SIB1 as the parameter TDD-Config.Based on this parameter, user equipment units will determine a largenumber of other settings, such as timing of uplink and downlink controlsignalling, sounding as well as Random Access Channel (RACH).

From an operator perspective, the TDD spectrum asset offers a potentialto select uplink and downlink resource configuration depending on thedeployment and services offered. A more symmetric configuration may bechosen for symmetric services such as Voice over Internet Protocol(VoIP), whereas a downlink heavy configuration may be suitable formultimedia distribution such as mobile television and web browsingproducing typically more data for downlink direction.

TDD systems built for wide area coverage, also known as macro basestations, typically tend to use the same TDD-config in all cells withinthe wireless communication system. This way interference between uplinkand downlink is avoided. At the same time, for other deployments, suchas femto, pico or micro base stations, these requirements may berelaxed, especially for the case with low to medium load. One reasonbeing that the propagation conditions are expected to very differentbetween base stations as well as the transmission powers. An importantscenario is femto base stations, which may be user deployed for examplein home environments, and where the number of user equipment unitsserved by each base station is small, and where the isolation betweendifferent base stations may be large in combination with low outputpowers.

A difference of packet data as compared to voice services is that it isbursty, on-off and asymmetric. During file download phase, the downlinktraffic is dominating whereas during upload phase, the uplink trafficwill dominate. Furthermore, Transmission Control Protocol (TCP), beingthe dominating transport protocol on the Internet, is elastic in itsnature. The TCP source probes the available bandwidth of the network.Because of this, the offered load does not stay constant over thedownload/upload procedure.

To maximize the efficiency and more importantly improve the userexperience in terms of file transfer time and latency, it is desirableto adapt the resource allocation to the actual resource needs in up- anddownlink, respectively. Obviously, performance benefits are achievableby adapting the resources to the actual load in uplink and downlink ascompared to using a fixed allocation. Furthermore, to be able to followrapid variations in the resource need, which are expected in packet dataapplications, a dynamic and efficient mechanism is needed so that theTDD-config may be updated efficiently and quickly.

Another important case where there is a need to adapt the TDD-config isthe case with interference between base stations separated largedistances. Due to atmospheric propagation phenomena, the isolationbetween base stations may vary, and at certain occasions, base stationsat very large distances may be heard by each other for a limited amountof time. It is inefficient to dimension a large guard period and use itall times, despite that a large guard period is only needed a smallfraction at a time. From this perspective, an efficient and rather rapidmechanism to change the TDD-Config is desirable.

There are also other parameters carried in system information that mayneed frequent updates. One is Random Access Channel (RACH) configurationused to determine the resources, time and frequency, for random accessattempt. It may be expected that the amount of user equipments, and/orother devices communicating over a wireless interface in the wirelesscommunication system will increase significantly in future whendifferent kind of Machine-to-Machine (M2M) applications will becomepopular. In this case, the RACH may be a bottleneck of the system andthus the network needs dimension RACH allocation adaptively.

A third motivator for rapid system information changes may be the desireto save power in the base station. At times of low or non-existent loadin a cell, the base station may want to adjust certain parameters of thecell, such that electrical power may be saved.

Thus, there are situations when there is a need to change values ofsystem information parameters. A particular, but non-limiting exampleconcerns the dynamic-TDD case above, where there may be a desire todynamically change system information parameters rather frequently. Inparticular, it may be noted that in dynamic-TDD, it may be a desire tochange system information parameters, even as often as once everysecond, or even more frequently. A third non-limiting example concernsenergy efficiency in the base station, where e.g. the number of usedantenna ports, carrier bandwidth or alike could be changed.

As will be further described below, the previously known method forsystem information change is too time consuming, inefficient andinapplicable.

First, in prior art, the system InfoValueTag may be incremented when thesystem info is changed. Since systemInfoValueTag has 32 values in LTERRC, this means that system information may be changed only 31 times in3 hours resulting the minimum average validity period of 5.6 minutes foreach set of system information parameters. Some changes of parameterscould hypothetically occur faster, however with the expense that othersets of parameters would then have to be valid for a longer period. Inany case, the value tag of 5 bits together with the 3 hour validity doesnot allow for very frequent system information changes.

If a value tag would be reused for two different sets of systeminformation parameters within 3 hours, there is a risk that a userequipment uses the wrong set of parameters in its communication with thewireless communication system. Depending on the mismatch theconsequences could be arbitrarily severe.

Validity times in the order of minutes rather than seconds may for someparameters be too long, i.e. there it is a need to change the parametersmore dynamically. Such parameters may comprise, but are not limited to,e.g. RACH parameters or TDD configuration.

Further the user equipment is instructed to read the whole systeminformation if the systemInfoValueTag has changed from a previous value.

As a further issue, it is to be noted that there is a period after themodification border during which the user equipment may have the wrongsystem information parameters. If system information is changed rarely,e.g. once in an hour or so, the relative time during which the userequipment uses wrong values may not be that detrimental. However, if theperiodicity of the message containing the relevant parameters is e.g.320 milliseconds, then this period is not negligible if the parameterchange period is counted in seconds rather than hours.

As a non-limiting example, due to changes in traffic load, the networkmay want to change TDD configuration. Another possibility is that due tointerference, e.g. temporary interference between uplink and downlink(base station-to-base station or UE-to-UE), the TDD guard period (GP)between uplink and downlink needs to be increased, or perhaps decreaseddue to the absence of such interference. As mentioned above, this avoidsoperating the system at all with an un-necessarily large guard period.

The corresponding TDD parameters are in in SIB1 having 7 differentvalues for uplink/downlink configuration and 9 values for the specialsub frame configuration including length of the guard period. Readingall system information blocks take time, which in turn makes the periodwhen the user equipment have wrong system information long. Also readingthe whole system information consumes the batteries of the userequipment.

Therefore, and with the TDD configuration change as a non-limitingexample, the user equipment may operate with the wrong configurationuntil it has re-read SIB1, wherein the user equipment re-read all othersystem information, even if that system information has not changed.

Further, there is no method to quickly inform the user equipment that itshould change the parameter values in its configuration. It may be thatthe base station detects that the user equipment has e.g. wrong TDDconfiguration.

One existing way to inform the user equipment about correctconfiguration is to send RRCConnectionReconfiguration withmobilityControl field, i.e. to perform an “intra-Cell handover”. Thisoperation will result the user equipment to receive updated systeminformation parameters. However, this handover (back) to the currentcell results in some procedures such as Random Access and/or reset ofRLC, Packet Data Convergence Protocol (PDCP) and MAC which may beunnecessary. Furthermore, the user equipment needs to be in connectedstate for enabling the reconfiguration.

The current method of notifying user equipment units of an upcomingchange is also rather costly in terms of radio resources, in case thechanges occur frequently. This is particularly true since every pagingslot needs to be used for sending the indication carried in a Pagingmessage, during the change period prior to the change. In addition,paging all user equipment units often, such as e.g. every modificationperiod, consume resources that could be otherwise used for datatransmission.

Therefore, there is a need for a new method for system informationchange, where it is possible to quickly set values of system informationparameters without the aforementioned problems occurring. In particular,there is a need for a solution where system information may be changedas often as e.g. once a second or even more frequently without runninginto the aforementioned problems.

SUMMARY

It is therefore an object to obviate at least some of the previouslydescribed disadvantages and to improve the performance in a wirelesscommunication system.

According to a first aspect, the object is achieved by a method in auser equipment. The method aims at setting values of system parametersused within a wireless communication system. The method comprisesreceiving a first set of parameter values and an associated first tag,from a base station. The received first set of parameter values and theassociated first tag are then stored by the user equipment in e.g. alook-up table in a memory. Further, also a second set of parametervalues and an associated second tag are received from the base stationand stored by the user equipment. When a command for setting the valuesof system parameters is received from the base station, which commandcomprises a command tag, the user equipment apply the set of parametervalues which is associated with the tag corresponding to the receivedcommand tag. Thus, the first set of parameter values, associated withthe stored first tag may be applied if the stored first tag correspondsto the received command tag. Alternatively, the second set of parametervalues, associated with the stored second tag may be applied, if thestored second tag corresponds to the received command tag.

According to a second aspect, the object is achieved by a userequipment. The user equipment is configured for setting values of systemparameters used within a wireless communication system. The userequipment comprises a receiver. The receiver is configured to receive afirst set of parameter values and an associated first tag and a secondset of parameter values and an associated second tag, from a basestation. Further, the receiver is also configured to receive a commandcomprising a command tag from the base station. The user equipmentfurther comprises a memory configured to store the received sets ofparameter values and the tag associated with each respective set.Further, the user equipment also comprises a processing circuit. Theprocessing circuit is configured to apply the first set of parametervalues associated with the stored first tag if the stored first tag iscorresponding to the received command tag or applying the second set ofparameter values associated with the stored second tag if the storedsecond tag is corresponding to the received command tag.

According to a third aspect, the object is achieved by a method in abase station. The method aims at setting values of system parametersused within a wireless communication system. The method comprisestransmitting a first set of parameter values and an associated firsttag, to be received by a user equipment. Also, the method comprisestransmitting a second set of parameter values and an associated secondtag, to be received by the user equipment. Further, the method comprisestransmitting a command comprising a command tag associated with the setof parameter values to be applied within the wireless communicationsystem.

According to a fourth aspect, the object is achieved by a base station.The base station is configured for setting values of system parametersused within a wireless communication system. The base station comprisesa transmitter. The transmitter is configured to transmit a set ofparameter values, associated with a tag. The transmitter is furtherconfigured to transmit a command comprising a command tag associatedwith the set of parameter values to be applied within the wirelesscommunication system.

Embodiments of the present methods and nodes enable the possibility toperform system information change more efficiently. By enabling the userequipment to read the values of the system information parameters inadvance, before they are actually to be applied, and associating eachsuch set of parameter values with a tag, it is possible to quicklyswitch from one set of parameter values to another set of parametervalues by only transmitting a tag corresponding to the set of parametervalues to be applied. Thereby is it possible to dynamically adapt thesystem parameters within a cell for optimal performance e.g. by togglingbetween different values related to the system information. The userequipment does not have to re-read the set of values to be applied everytime, which save energy resources of the user equipment as well as time.By transmitting a tag representing a set of parameter values, instead ofthe parameter values as such when system information change is desired,overhead transmission in the system is decreased, leading to less (riskof) interference, less occupation of signalling resources, less energyconsumption at the base station and an overall increased efficiency.Thereby is an improved performance in a wireless communication systemachieved.

Other objects, advantages and novel features will become apparent fromthe following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present methods and nodes are described in moredetail with reference to attached drawings illustrating exemplaryembodiments and in which:

FIG. 1A is a schematic block diagram illustrating a change of systeminformation in a wireless communication network, according to prior art.

FIG. 1B is a schematic block diagram illustrating a frame structure in awireless communication network, according to prior art.

FIG. 1C is a schematic block diagram illustrating uplink/downlinkconfigurations in a wireless communication network according to priorart.

FIG. 1D is a schematic block diagram illustrating special subframeconfigurations for normal subframe in a wireless communication network,according to prior art.

FIG. 2 is a schematic block diagram illustrating a wirelesscommunication network according to some embodiments.

FIG. 3 is a combined flow chart and block diagram illustrating a methodaccording to some embodiments.

FIG. 4 is a schematic block diagram illustrating periodic indications ofsystem information change, or toggling according to some embodiments.

FIG. 5 is a flow chart illustrating an embodiment of the present methodin the user equipment, according to some embodiments.

FIG. 6 is a schematic block diagram illustrating a user equipmentaccording to some embodiments.

FIG. 7 is a flow chart illustrating an embodiment of the present methodin a base station according to some embodiments.

FIG. 8 is a schematic block diagram illustrating a base stationaccording to some embodiments.

DETAILED DESCRIPTION

The present methods and nodes are defined as a user equipment, a methodin a user equipment, a base station and a method in a base station forsetting values of system parameters used within a wireless communicationsystem. The herein disclosed may be put into practice in the embodimentsdescribed below. These methods and nodes may, however, be embodied inmany different forms and are not to be considered as limited to theembodiments set forth herein; rather, these embodiments are provided sothat this disclosure will be thorough and complete, and convey the scopeof the claims to those skilled in the art.

FIG. 2 depicts a wireless communication system 100, based on at leastone of such technologies as 3GPP LTE and its evolutions e.g.LTE-Advanced, but also Evolved Universal Terrestrial Radio AccessNetwork (E-UTRAN), Universal Mobile Telecommunications System (UMTS),Global System for Mobile communications/Enhanced Data rate for GSMEvolution (GSM/EDGE), Wideband Code Division Multiple Access (WCDMA),Worldwide Interoperability for Microwave Access (WiMax), or Ultra MobileBroadband (UMB), or according to any other wireless communicationtechnology etc, just to mention some few non limiting examples.

The wireless communication system 100 may be configured to operateaccording to the Time Division Duplex (TDD) and/or the FrequencyDivision Duplex (FDD) principle, according to different embodiments.

TDD is an application of time-division multiplexing to separate uplinkand downlink frames in time, possibly with a guard period situated inthe time domain between the uplink and downlink frames. FDD means thatthe transmitter and receiver operate at different carrier frequencies.

The purpose of the illustration in FIG. 2 is to provide a generaloverview of the present methods and the functionalities involved. Theherein described methods and nodes are elaborated with specificreference to LTE networks. Thus the wireless communication system 100 isdescribed as an LTE system such as e.g. a 3GPP/e-UTRAN environmentthroughout the rest of the disclosure, for enhanced comprehension andreadability. However, the corresponding concept may also be applied inany other wireless system 100, based on other radio access technology,such as e.g. the ones previously enumerated.

The wireless communication system 100 comprises a base station 110, anda user equipment 120, arranged to communicate with each other. The userequipment 120 is situated in a cell 130, served by the base station 110.Although only one single cell 130 is illustrated in FIG. 2, which cell130 is served by the base station 110, it is to be understood that thebase station 120 may be in charge of more than one cell 130.

Further, in the illustrated non limiting exemplary embodiment of thewireless communication system 100 is only one instance of a base station110 and one instance of a user equipment 120 depicted, in order toaugment the understanding of the present methods and nodes. However, itis to be noted that the illustrated setting of network nodes 110, 120 isonly exemplary. The wireless communication system 100 may comprisefurther network nodes 110, 120 such as base stations 110 and/or userequipment 120 in any number and combination.

The user equipment 120 is configured to transmit uplink radio signalscomprising information data to be received by the base station 110.Further, the user equipment 120 is also configured to receive downlinkradio signals comprising information data transmitted by the basestation 110.

The user equipment 120 may be represented by e.g. a wirelesscommunication terminal, a mobile node, a mobile station, a mobilecellular phone, a Personal Digital Assistant (PDA), a wireless platform,a laptop, a beacon, a computer or any other kind of device configured tocommunicate wirelessly with the base station 110.

The base station 110 may be represented by e.g. Radio Base Stations(RBSs), macro base stations, NodeBs, evolved Node Bs (eNBs, or eNodeBs), base transceiver stations, Access Point Base Stations, base stationrouters, micro base stations, pico base stations, femto base stations,Home eNodeBs, relays and/or repeaters, sensor, beacon device or anyother network node configured for communication or signal transmissionover a wireless interface, depending e.g. of the radio access technologyand terminology used.

Herein, a connection between any network nodes such as the base station110 and/or the user equipment 120 may comprise e.g. a logical connectionsuch as e.g. a connection via higher-layer protocols through one or morenetwork nodes, or a physical connection such as e.g. a directconnection.

FIG. 3 illustrates an exemplary embodiment of the present methods andnodes for making the system information change more efficient maycomprise one or more of the following aspects:

A tag that may take at least two distinct values may be defined, whereeach value of the tag is associated with at least one parameter value ofsystem information, or a set of such system information parametervalues.

The base station 110 may transmit the set of parameter values and theassociated tag, to be received by the user equipment 120. Suchtransmission may comprise one set of parameter values and the associatedtag, or several sets of parameter values, each associated with adistinct tag which is also transmitted in conjunction with thecorresponding set of parameter values with which they respectively areassociated.

The user equipment 120 may receive and store both the set of systeminformation parameter values and the associated tag.

Upon detection that the value of a command tag has changed, or that acommand tag associated with a different set of parameter values than isconcurrently utilized by the user equipment 120 is received, the userequipment 120 may change the parameters and/or parameter values used byit, without re-reading the whole system information. The user equipment120 may take the other, currently valid set of system informationparameter values into use directly, without having to re-read it as itis already stored in a memory by the user equipment 120. Therebyprocessing power and time are saved. Also, an instant change of systeminformation and/or toggling between different sets of system informationparameters is enabled. It is thereby possible to utilize the optimal setof system information parameter values at any time within the cell 130.

Alternatively, according to some embodiments, the application of theother set of parameter values may be delayed for some configurable orpre-defined period of time after reception of the command tag. In anycase, the present methods render it possible to toggle between differentsets of system information parameter values without re-reading systeminformation. Thereby, an improved performance within the wirelesscommunication system 100 is achieved.

A system information change may according to some embodiments benotified during one first time period, and the actual change of systeminformation parameters may be performed in the next time period, or anylater time period.

Further, the base station 110 continuously, or at certain time intervalsmay determine which set of parameter values to be applied within thecell 130, for the particular user equipment 120, for a predefined orconfigurable subset of user equipment 120 situated within the cell 130,or for all user equipment 120 within the cell 130, according todifferent embodiments.

When the base station 110 has determined which set of parameter valuesto be applied, it may generate a command comprising a command tagassociated with the set of parameter values to be applied, according tosome embodiments.

Secondly, and according to another aspect of some embodiments, aconfigurable meaning of MIB information may be provided. Thereby may theuser equipment 120 according to some embodiments be configured tointerpret a bit or code-point value received in MIB in different waysdepending on the received configuration. Further, the user equipment 120may receive information how to interpret bits or code point values inMIB, which information may be received in another form of message. In aparticular embodiment, one or multiple bits in the MIB may be configuredto be associated with one system information parameter value, or a setof such system information parameter values. When the user equipment 120receives a code point of the aforementioned MIB bits, it may accordingto some embodiments change the value of the system information parametervalue, or set of such system information parameter values according tothe aforementioned configuration. Thus, and according to this aspect,the MIB bits may be configured to be used as a command tag. However, ina different configuration, the same bits may be configured for another,arbitrary purpose.

Thus, embodiments of the present methods and nodes are configured todefine a command tag or other dynamic indicator in the MIB, and it isrealized that MIB comprises some non-reserved bits, which also may bereferred to as Spares, that may be used e.g. for this purpose in afuture release of the LTE RRC protocol. However, reserving these scarcebits for a particular purpose may not be desirable, as there might bemultiple conflicting needs to comprise additional indicators orinformation in MIB.

In yet another aspect, the aforementioned command tag associated with aset of parameter values may be conveyed in a PDCCH indication and thisindication may be configured by the network according to someembodiments. The indication may be used for indicating dynamic systeminformation change according to the present method. In embodiments ofthis aspect, the configuration may comprise configuring a periodicityi.e. time-slots, at which the indication may occur, the detailed systeminformation aspects associated with the indication etc. In furtherembodiments, the indication or command tag may be conveyed in a Pagingmessage, in a MAC control element, or using an RRC message according todifferent alternative embodiments.

Thus, there are multiple ways of providing the parameter values andcorresponding associated command tags to the user equipment 120, such ase.g. MIB code-points, PDCCH, MAC control element indications, or RRCmessages, just to mention some options. These ways further comprisessignalling this configuration to the specific user equipment 120 with adedicated message, or to broadcast the configuration on a broadcastchannel, such that all user equipment 120 within the cell 130 mayreceive it. If provided on a broadcast channel, the configuration may beprovided in a System Information Block, SIB.

In addition, according to some embodiments, a method of signalling acommand tag-reading period from the base station 110 to the userequipment 120 that is different from the BCCH modification period, wherethe user equipment 120 is required to read the value of the command tag,the configurable MIB bits, PDCCH indication, Paging message or similarat particular instances, is provided. This is further illustrated inFIG. 4, illustrating some exemplary tag reading periods, which intensitymay be predefined or configurable. The user equipment 120 thus may readthe value of the command tag at these occasions. If the user equipment120 finds that the command tag, comprised e.g. in MIB bits or similarindication has changed, the user equipment 120 may parse the new commandtag against stored tags. If a corresponding stored tag is encountered,the set of parameter values associated with that tag be taken into usewithout re-reading system information. The command tag-reading periodmay be signalled from the base station 110 to the user equipment 120 bya dedicated message, or by a broadcast message according to differentembodiments.

Returning now to FIG. 3, in yet another embodiment, it may occur thatsome user equipment units 120 have not acquired the correct systeminformation for some reason. Such reasons may comprise e.g. that theuser equipment 120 is in idle mode, that the user equipment 120 may notfollow the dynamic changes of system information, and therefore wouldbenefit from receiving the aforementioned updates once entering theconnected state. In the present context, idle mode is the state of theuser equipment 120 when it is switched on but does not have anyestablished RRC connection. When in connected mode, the user equipment120 is switched on and an RRC connection is established. Thus, a userequipment 120 that has not acquired the correct system information maybe updated with correct system information, such as e.g. the TDDconfiguration, by sending a dedicated message comprising the correct orupdated system information parameter values. The benefit of thisapproach is that no handover is needed to update user equipment 120 thatfor some reason or another have not acquired the system information thatis currently in use.

Thus, to summarise some exemplary aspects according to some embodimentsof the present methods, the method in a user equipment 120 may comprisestoring multiple sets of system information parameter values, andreceiving an indication such as a command tag, that one of these sets isto be applied and utilized, and taking that set into use. Embodiments ofmethods performed in the base station 110 comprises signalling one orseveral sets of system information parameter values, each associatedwith a distinct tag, which are to be received and stored by the userequipment 120, or a subset of user equipment 120 within the cell 130.MIB bits and corresponding code-points may be configured, such that theymay be utilised for multiple purposes, wherein one purpose is tocomprise the command tag associated with the set of parameters to beapplied according to some embodiments. Further, a command tag-readingperiod may be signalled from the base station 110 to the user equipment120 according to some embodiments. The signalled command tag-readingperiod may define when the user equipment 120 may read theaforementioned indications or MIB code-points. In some furtherembodiments, additional actions for conveying the indication, or commandtag, using PDCCH, Paging, MAC control elements or RRC signalling may becomprised. Further, according to some embodiments, a system parameterconfiguration of a particular user equipment 120, such as e.g. TDDconfiguration may be corrected.

Further exemplary non-limiting, non-exclusive examples of embodimentswill now be disclosed and described more in detail, with reference madein particular to FIG. 2, FIG. 3 and FIG. 4.

Consider the user equipment 120 in the cell 130, as illustrated in FIG.2. The user equipment 120 may preferably be in connected state, i.e. theuser equipment 120 may be registered and known to the base station 110in control of the cell 130, but it may also occasionally be in idlestate. Here, an embodiment is described addressing a single userequipment 120 in one cell 130. As illustrated in FIG. 2, the userequipment 120 receives a first set of system information parametervalues, set 1, associated with a first tag A.

The user equipment 120 receives, or reads, system information parametervalues of the first set, set 1, associated with the first tag A. Also,the user equipment 120 receives, or reads, system information parametervalues of a second set, set 2, associated with a second tag B.

The first set and the second set of system information parameter valuesmay differ in that at least one parameter has a different value in oneof the first or the second sets. It may also be that multiple parameterstake different values in the two sets. Or, it may be that some parameteris present in one of the sets, but not in the other set. The sets areassociated with different tags, e.g. so that a first set of parametersis tagged with the value “A”, and a second set of system informationparameters is tagged with the tag “B”, such that also the tags arereceived by the user equipment 120.

The system information parameter values and the respective associatedtag A, B may be transmitted to the user equipment 120 by many differentmeans according to different embodiments. For example, the first setassociated with the tag A may be broadcasted in the cell 130, while thesecond set associated with the tag B may be provided in many differentways. For example, it may be that only the parameters and/or parametervalues that are different between the sets are signalled to theconcerned user equipment 120. Thereby may resources and time be saved asless information has to be transmitted. Further, the overall systemefficiency may be increased as less overhead information has to betransmitted and also the potential risk of interference may bedecreased.

To be specific, it may be that all parameter values in the first and thesecond sets are the same, except those defining the TDD configuration.In such a case, the TDD configuration of the second set may be providedon the same broadcast channel, in a SIB, or it may be provided to theuser equipment 120 using dedicated signalling. If provided over abroadcast channel, the parameters defining the configuration of thesecond set of parameters, i.e. the ones differing from the first set ofparameters may preferably be provided as optional extensions to thebroadcasted messages carrying the configuration of the first set.Furthermore, according to some embodiments may both the first set andthe second set be provided during different modification periods on thebroadcast channel. Then the tags A, B to be associated with therespective sets may be the value tags carried in SIB1 messages,correspondingly, according to some embodiments.

Further, if there are additional parameter values that differ betweenthe sets, then those may also be provided to the user equipment 120.There may also be additional sets, such as a third, a fourth etc. thatmay be conveyed to the user equipment 120 with associated tags. Thus theuser equipment 120 may be aware of different sets of system informationparameter values such as e.g. two such sets, and the user equipment 120may have to know which of the sets to be applied. It is to be noted thatany number of sets of system information parameter values andcorresponding tag may be applied within the present method.

According to some embodiments, there may be provided means forsignalling which of the sets that is currently in use. Thus the basestation 110 may provide a signalling method for indicating that the userequipment 120 may use the first set, and when changed, the userequipment 120 may be informed that the user equipment 120 may use thesecond set of parameter values.

A particular benefit of some embodiments is that the user equipment 120may take the other, e.g. second set into use, upon reception of theindication, i.e. command tag, since the user equipment 120 has storedthe set of system information and the associated tag. Thus an indicationof changed system information implies that the user equipment 120 mayhave to re-read system information after the change of modificationperiod according to some embodiments.

Thus, embodiments of the present method therefore provide fast togglingbetween different sets of system information. The notation “take intouse” does not necessarily imply that the user equipment 120 needs totake the set “B” into use instantly, at the reception of the commandtag. The user equipment 120 may according to some embodiments delay thechange of system information parameters for a period of time, such ase.g. 40 or 80 milliseconds, after the reception of the command tag.Further, the command tag may comprise information of a point in timewhen the set of parameter values are to be utilised. It is to be notedthat these time periods/time points mentioned in the present context aremerely some non-limiting examples. The time delay may comprise any otherarbitrary period of time, or point in time.

The command tag for toggling between different system informationversions may be provided, e.g., by that a ValueTag is toggled in SIB1.In the present context, the expressions command tag and ValueTag maycomprise the same subject-matter and may sometimes be used as synonyms.

However, it may be realized that there are other ways of conveying thisinformation that may have particular benefits. It may further be notedthat, if the valueTag (command tag) in SIB1 would be used directly as ameans for indicating the “toggling” above, it may result in “confusion”among some user equipment 120, for example user equipment which are notconfigured according to the present method. Thus, a plurality of meansfor indicating the toggling or change may be utilized, as furtherdescribed below, according to some embodiments.

According to some embodiments related to this issue, a number of sparebits available in MIB may be identified. It may further be observed thatMIB is transmitted more frequently than SIB1 (40 milliseconds versus 80milliseconds), and it may therefore be beneficial to provide theindication in MIB instead of in SIB1, as a shift between systeminformation parameters may be changed faster. In addition, it may benoted that the error coding of the MIB repetitions are typically sorobust, since a MIB may be decodable also outside the serving cell 130,i.e. also in neighbour cells, that a user equipment 120 in reasonableproximity to the transmitting base station 110 may often receive the MIBwithout any repetition. In such cases, the user equipment 120 may beable to successfully decode MIB within one subframe of 1 millisecondevery 40th millisecond. Furthermore, the repetitions of the MIB may beself-decodable, thereby reducing the periodicity of MIB reception toe.g. 10 milliseconds according to some embodiments. Thus, MIB mayprovide good means for conveying which system information is in use, ifroom is given for signalling the aforementioned flag in MIB.

Now, it may not be desirable to reserve any scarce bits or code-pointsin MIB for any such specific purpose as e.g. a system information“flag”.

Embodiments of the present method may be adapted for configuring themeaning of MIB bits (code points), where a user equipment 120 that mayreceive this configuration may be configured to interpret bit (codepoint) values in MIB according to the configuration. The configurationmay be provided e.g. by higher-layer signalling, either over a broadcastchannel e.g. in a SIB, or using a dedicated message, according to someembodiments.

In a particular embodiment, this configuration provides bit (code point)values in MIB associated with sets of system information, where each bit(code point) value is associated with a particular set of systeminformation. For example, code point 010 of three bits may be connectedto system information set “A”, and code point 011 may be connected tosystem information set “B”. It is to be noted, that this method ofconfiguring the different code points in MIB are then not limited to thevarious embodiments related to system information change, but the samecode points, in this exemplary illustration, 010 and 011 may, in adifferent cell or in the same cell 130, but at a different time, beconfigured to represent some other information. As non-limitingexamples, the same code point i.e. 010 and 011 may then indicate “cellbarred”, or “energy saving is on”, or whatever upcoming feature that isconsidered necessary to broadcast in MIB. This embodiment may thereforeallow for particular flexibility in signalling by reusing valuable bitsin MIB for the particular needs at hand.

It is thus to be noted that the dynamic configuration of the bits (codepoints) in MIB according to some embodiments may determine how toutilize the available non-reserved bits (code points), or spares, inMIB.

In a further action the base station 110 may transmit the informationconcerning how to utilize the available non-reserved bits in MIB, to bereceived by the user equipment 120. Such information may be transmittedin a SIB message, according to some embodiments.

In a further action a MIB message comprising information in thenon-reserved bits may be transmitted from the base station 110 to bereceived at the user equipment 120. The non-reserved bits of the MIB maythen be utilized, i.e. encoded according to the previously determinedpurpose.

Thereby the user equipment 120 is enabled to receive informationcomprised in the non-reserved bits of the MIB and utilize them, i.e.decode them according to the previously received information concerninghow to utilize the non-reserved MIB bits.

The dynamically configurable bits in MIB may be utilized e.g. to specifywhat system information blocks are in use in the cell 130, and/or howthey may be accessed, according to some embodiments.

In addition to the embodiments comprising the ValueTag in the embodimentinvolving communication in SIB1, and/or the embodiment involvingcommunication in MIB described above, it is herein further described andcomprised embodiments wherein the sets of system information may be usedby the user equipment 120. For example, there may be a new indication onPDCCH, conveyed e.g. with a new RNTI designed for the purpose ofconveying this information to the user equipment 120. Alternatively, theinformation may be provided in a paging message according to someembodiments. In yet further embodiments, information concerning whichsystem information set to be utilized may be conveyed by using a MACcontrol element, or an RRC message.

However, in order for the base station 110 to control when and how oftensystem information is to be changed within the cell 130, the basestation 110 may configure the user equipment 120 to read or receive therelevant command tag or other information that may indicate which systeminformation to utilize, at particular time instants or with a particularperiodicity, according to some embodiments. Such features may beparticularly applicable when the indication is provided by means ofbroadcast within the cell 130, such as e.g. a broadcast using MIB asdescribed above, a broadcast of a command tag or broadcasting of acommand tag over PDCCH, or similar. Thereby, according to someembodiments, the base station 110 may easily decide how frequently itwants to be able to change system information and thereby making theinformation change available to the user equipments 120 within the cell130.

In response to receiving the configuration about this periodicity ortime-instances, the user equipment 120 may read the relevant informationon a broadcasted channel, or any other appropriate channel, to find outwhat system information to utilize, i.e. if the user equipment 120 is tochange system information. The benefit of this embodiment is that thebase station 110 may easily trade between the desire to change systeminformation frequently, and the desire to allow the user equipment 120,or sets of user equipments, to save battery resources by not waking uptoo frequently for broadcast information reading. For example, if thebase station 110 sees no immediate reason for changing systeminformation, it may set the period to infinity, or to a high value, i.e.disabling the reading of the system information and/or systeminformation version (command) tag and/or change information, accordingto some embodiments. In contrast, if the base station 110 wants tochange system information frequently, it may set this period to a lowvalue, i.e. that the reading times occur frequently. The reading of thecommand tag information may also be aligned with a disruptedtransmission DRX mechanism in such a way that the user equipment 120 mayreceive the command tag when it is anyway active in monitoring PDCCH.

The idle user equipment 120 may have a wrong configuration of systeminformation parameters or values of such parameters when the embodimentof the present method is applied. This may be the case e.g. if it isdefined that only user equipment 120 in connected mode, or a specificconfigured set of user equipments 120 may be required to follow thedynamic system information changes herein described. According to someembodiments, the correct parameters may be indicated with a dedicatedapproach. For example, the parameters may be provided when the userequipments 120 performs Random Access. The indication may be e.g. aspecific CRNTI on PDCCH, a MAC control element or a RRC message,according to different embodiments. Furthermore, such dedicated messagemay be limited to be utilized only in specific occasions such as Message4 (contention resolution) in Random Access procedure.

Some legacy user equipment, e.g. according to Release 8 or 9 of LTE, maynot be able to receive dedicated signalling according to the discussedembodiments. In such scenario, such user equipments may be scheduledassuming a specific default configuration over some period and finallywhen they are connected, RRCConnectionReconfiguration may be applied.Alternatively, scheduling of such legacy user equipment may be delayedto some specific time point, when system information is changed usingexisting methods and legacy user equipments have received updatedinformation. The “default” configuration may be selected in such a waythat user equipment measurements are not disturbed.

FIG. 5 is a flow chart illustrating embodiments of method actions501-509 in a user equipment 120. The method aims at setting values ofsystem parameters used within a wireless communication system 100. Theuser equipment 120 and a base station 110 are comprised in the wirelesscommunication system 100. The wireless communication network 100 may bee.g. an LTE radio network. The base station 110 may be e.g. an eNBaccording to some embodiments. The user equipment 120 may be mobiletelephone or similar. The method may be performed within a cell 130,served by the base station 110. A system information change mayaccording to some embodiments be notified during one first time period,and the actual change of system information parameters may be performedin the next time period, or any other later time period.

To appropriately set the values of system parameters, the method maycomprise a number of actions 501-509.

It is however to be noted that some of the described actions, e.g. anyof the actions 501-509 may be performed in a somewhat differentchronological order than the enumeration indicates and that some ofthem, e.g. action 505 and 507, are performed within some alternativeembodiments. Further, any, some or all actions, such as e.g. 501 and 503may be performed simultaneously or in a rearranged chronological order.The method may comprise the following actions:

Action 501—A first set of parameter values and an associated first tagare received from the base station 110.

Action 502—The received first set of parameter values and the associatedfirst tag are stored. The first set of parameter values and theassociated first tag may be stored in a memory comprised within the userequipment 120, or readily accessible to the user equipment 120. Theparameter values and the associated first tag may be stored e.g. in adatabase or a look-up table having the tag as input value, such that theparameter values associated with a certain tag may conveniently beretrieved.

Action 503—A second set of parameter values and an associated second tagare received from the base station 110. According to some embodiments,the parameter value, or values, which value, or values, differ from thereceived first set of parameter values may be received.

Thereby may redundant signalling and data processing be avoided orreduced, as the same parameter value may not be transmitted twice, ifthe values are the same in both the first set of parameter values andthe second set of parameter values.

Sometimes, the difference between the first set of parameter values andthe second set of parameter values is very small, for example only asmall part of the parameter values are changed at the time.

An illustrating non-limiting example is now discussed. Assume theparameters: “first parameter”={1,2,3,4}, “second parameter”={1,2,4},“third parameter”={1,2,3}, “fourth parameter”={q, r}.

The first set A may comprise first parameter=1, second parameter=2,third parameter=1. The second set B may comprise first parameter=1,second parameter=2, third parameter=3, fourth parameter=r. In suchscenario, then action 503 is to be performed, the third parameter=3 andthe fourth parameter=r may be transmitted as comprised in the second setB, i.e. the values of the second set, which are different from the firstset of parameter values.

Thereby, by only communicating the difference between the values offirst set of parameters and the second set, may communication resourcesbe saved.

Action 504—The received second set of parameter values and theassociated second tag are stored. The second set of parameter values andthe associated second tag may be stored in a memory comprised within theuser equipment 120, or readily accessible to the user equipment 120. Theparameter values and the associated second tag may be stored e.g. in adatabase or a look-up table having the tag as input value, such that theparameter values associated with a certain tag may conveniently beretrieved.

Action 505—This action may be performed within some alternativeembodiments. A configuration message may be received from the basestation 110. The configuration message may comprise information on howto interpret at least one code point in a set of bits, broadcasted inMIB.

The configuration message may be a broadcasted system informationmessage, or a dedicated signalling message.

Action 506—A command for setting the values of system parameters isreceived from the base station 110, which command comprises a commandtag. The command comprising the command tag, received from the basestation 110 may be comprised in one of: a System Information Block(SIB), a Master Information Block (MIB), a paging message, a MediumAccess Control (MAC) control message, a Radio Resource Control (RRC)control message, or a message on a Physical Downlink Control Channel(PDCCH).

The user equipment 120 may receive, from the base station 110,information on how and how often the user equipment 120 may receive, orread the command tag. This may be for example every 40 millisecond,every 80 millisecond or every 240 millisecond, just to mention somearbitrary and non-limiting examples. Further, such information maycomprise e.g. how to utilize non-reserved bits and/or code points, orspares, in MIB. According to some embodiments may the command tag becomprised in such a non-reserved bit of MIB transmitted to be receivedby the user equipment 120.

Action 507—This action may be performed within some alternativeembodiments. The command tag may be extracted from the set of bits inMIB, which may have been received from the base station 110 in action505, according to the information comprised in the configurationmessage.

Action 508—This action may be performed within some alternativeembodiments. The received command tag may be compared with the storedfirst and/or second tag. The comparison may be performed by parsing thecommand tag against the tags stored in the memory unit of the userequipment 120.

Action 509—The user equipment 120 applies the first set of parametervalues associated with the stored first tag, if the stored first tagcorresponds to the received command tag. If the stored second tagcorresponds to the received command tag, the user equipment 120 appliesthe second set of parameter values associated with the stored secondtag. The set of parameter values associated with the tag thatcorresponds to, e.g. is at least partly identical with the receivedcommand tag, may thus be applied.

Before applying the parameter values, the application of the parametervalues may be delayed for a period of time after the reception of thecommand comprising the command tag. The application of the parametervalues may alternatively be delayed until a certain point in time, whichhas been communicated to the user equipment 120 e.g. comprised in thecommand tag or transmitted together with the command tag from the basestation 110.

Thanks to embodiments of the present method, relevant parameter valuesof the system information may be changed swiftly and be adaptedinstantly for example when the load of the cell 130 varies, which renderan improved performance within the system 100.

Thereby system information change may be performed more efficiently anddynamically within the wireless communication system 100.

FIG. 6 schematically illustrates a user equipment 120. The userequipment 120 is configured to perform any, some or all of thepreviously described actions 501-509 in order to set values of systemparameters used within a wireless communication system 100. The userequipment 120 and a base station 110 are comprised in the wirelesscommunication system 100. The wireless communication network 100 may bee.g. an LTE radio network. The base station 110 may be e.g. an eNBaccording to some embodiments. The user equipment 120 may be mobiletelephone or similar. The method may be performed within a cell 130,served by the base station 110.

In order to perform the actions 501-509 correctly, the user equipment120 comprises a receiver 610. The receiver 610 is configured to receivea first set of parameter values and an associated first tag and a secondset of parameter values and an associated second tag, from the basestation 110. The receiver 610 is further configured to receive a commandcomprising a command tag from the base station 110. The user equipment120 further comprises a memory 625. The memory 625 is configured tostore the received sets of parameter values and the tag associated witheach respective set.

The memory 625 may comprise e.g. a semiconductor storage such asRandom-Access Memory (RAM), or Dynamic-RAM (DRAM). However, the memory625 may refer to other forms of temporary or permanent storage. Thememory 625 may comprise secondary storage devices such as e.g. hard diskdrives, optical disc drives, and other similar data storage devices orflash memory, just to mention some examples.

The user equipment 120 in addition also comprises a processing circuit620. The processing circuit 620 is configured to apply the first set ofparameter values associated with the stored first tag if the storedfirst tag is corresponding to the received command tag, or applying thesecond set of parameter values associated with the stored second tag ifthe stored second tag is corresponding to the received command tag.

The processing circuit 620 may be represented by e.g. a CentralProcessing Unit (CPU), a microprocessor, or other processing logic thatmay interpret and execute instructions. The processing circuit 620 mayperform data processing functions for inputting, outputting, andprocessing of data comprising data buffering and device controlfunctions, such as call processing control, user interface control, orthe like.

The processing circuit 620 may further be configured to delay theapplication of the parameter values for a period of time after thereception of the command tag, according to some embodiments.

The receiver 610 may be further configured to receive the parametervalues whose values differ from the received first set of parametervalues.

The user equipment 120 and/or the receiver 610 comprised within the userequipment 120 may be further configured to receive the commandcomprising the command tag from the base station 110, comprised in oneof: a System Information Block (SIB), a Master Information Block (MIB),a paging message, a Medium Access Control (MAC) control message, a RadioResource Control (RRC) control message, or a message on a PhysicalDownlink Control Channel (PDCCH).

The receiver 610 may be further configured to receive a configurationmessage from the base station 110, comprising information on how tointerpret at least one code point in a set of bits, broadcasted in MIB.Further, according to some embodiments, the processing circuit 620 maybe further configured to extract the command tag from the set of bits inMIB received from the base station 110, according to the information inthe configuration message.

The receiver 610 may be further configured to receive, from the basestation 110, information on how and when the user equipment 120 mayreceive the command tag, according to some embodiments.

The configuration message may be one of a broadcasted system informationmessage, or a dedicated signalling message according to someembodiments.

Further, according to some embodiments, the user equipment 120 maycomprise a transmitter 630. The transmitter 630 may be configured totransmit signals to the base station 110 over a radio interface.

It is to be noted that any internal electronics of the user equipment120, not completely necessary for understanding the present methodaccording to actions 501-509 has been omitted from FIG. 6, for clarityreasons.

Further, it is to be noted that some of the described units 610-630comprised within the user equipment 120 in the wireless communicationsystem 100 are to be regarded as separate logical entities but not withnecessity separate physical entities. To mention just one example, thereceiver 610 and the transmitter 630 may be comprised or co-arrangedwithin the same physical unit, a transceiver, which may comprise atransmitter circuit and a receiver circuit, which transmits outgoingradio frequency signals and receives incoming radio frequency signals,respectively, via an antenna. The radio frequency signals transmittedbetween the user equipment 120, and/or the base station 110 may compriseboth traffic and control signals e.g. paging signals/messages forincoming calls, which may be used to establish and maintain a voice callcommunication with another party or to transmit and/or receive data,such as SMS, e-mail or MMS messages, with a remote user equipment.

The actions 501-509 in the user equipment 120 may be implemented throughone or more processing circuit 620 in the user equipment 120, togetherwith computer program code for performing the functions of the presentactions 501-509. Thus a computer program product, comprisinginstructions for performing the actions 501-509 in the user equipment120 may perform those actions in order to set values of systemparameters used within the wireless communication system 100, when thecomputer program product is loaded into the processing circuit 620.

The computer program product mentioned above may be provided forinstance in the form of a data carrier carrying computer program codefor performing the method actions according to the present method whenbeing loaded into the processing circuit 620. The data carrier may bee.g. computer readable storage medium such as a hard disk, a CD ROMdisc, a memory stick, an optical storage device, a magnetic storagedevice or any other appropriate medium such as a disk or tape that mayhold machine readable data. The computer program code may furthermore beprovided as program code on a server and downloaded to the userequipment 120 remotely over a wireless or wired connection.

FIG. 7 is a flow chart illustrating embodiments of method actions701-705 in a base station 110. The actions 701-705 aims at settingvalues of system parameters used within a wireless communication system100.

The user equipment 120 and a base station 110 are comprised in thewireless communication system 100. The wireless communication network100 may be e.g. an LTE radio network. The base station 110 may be e.g.an eNB according to some embodiments. The user equipment 120 may bemobile telephone or similar. The method may be performed within a cell130, served by the base station 110.

To appropriately set values of system parameters used within a wirelesscommunication system 100, the method may comprise a number of actions701-705.

It is however to be noted that some of the described method actions,e.g. action 701-705 may be performed in a somewhat differentchronological order than the enumeration suggests and that some of them,e.g. action 701 and 702, may be performed simultaneously or in arearranged chronological order. Further, some of the actions such ase.g. action 703 and/or 704 may be performed within some alternative. Themethod may comprise the following actions:

Action 701—A first set of parameter values and an associated first tagare transmitted. The first set of parameter values and the associatedfirst tag may be transmitted to be received by the user equipment 120,or a subset of user equipments 120 within the cell 130.

Action 702—A second set of parameter values and an associated second tagare transmitted. The second set of parameter values and the associatedsecond tag may be transmitted to be received by the user equipment 120,or a subset of user equipment 120 within the cell 130.

The second set of parameter values may comprise the parameter valueswhose values in the second set differ from the values of the parameterstransmitted in the first set of parameter values, according to someembodiments.

Action 703—This action may be performed within some alternativeembodiments. A configuration message may be transmitted. Theconfiguration message may comprise information concerning how tointerpret at least one code point in a set of bits transmitted in MIB.

Action 704—This action may be performed within some alternativeembodiments. The user equipment 120 may be informed at which point intime to read the command tag. Further, the user equipment 120 may alsobe informed how to receive and/or read the command tag. Thus, the userequipment 120 may be informed that the command tag is to be received inone of: a System Information Block (SIB), a Master Information Block(MIB), a paging message, a Medium Access Control (MAC) control message,a Radio Resource Control (RRC) control message, or a message on aPhysical Downlink Control Channel (PDCCH).

Action 705—A command comprising a command tag associated with the set ofparameter values to be applied within the wireless communication system100 is transmitted. The transmission of the command comprising thecommand tag may be performed to a subset of user equipment 120 situatedwithin a cell 130 served by the base station 110.

The transmission of the command may according to some embodimentscomprise a time or a time delay, indicating when the set of parametervalues associated with a tag corresponding to the command tag is to beapplied by the user equipment 120, after having received the command.Thus the application of the parameter values may be delayed for a periodof time after the reception of the command comprising the command tag.

The command comprising the command tag may be comprised in one of: aSystem Information Block (SIB), a Master Information Block (MIB), apaging message, a Medium Access Control (MAC) control message, a RadioResource Control (RRC) control message, or a message on a PhysicalDownlink Control Channel (PDCCH).

The transmission comprising the command tag may comprise a transmissionof a set of bits in MIB comprising the command tag, according to theinformation in the configuration message.

FIG. 8 schematically illustrates a base station 110. The base station110 is configured to perform any, some or all of the actions 701-705, inorder to set values of system parameters used within a wirelesscommunication system 100.

The base station 110 and a user equipment 120 are comprised in thewireless communication system 100. The wireless communication network100 may be e.g. an LTE radio network. The base station 110 may be e.g.an eNB according to some embodiments. The user equipment 120 may bemobile telephone or similar. The method may be performed within a cell130, served by the base station 110.

In order to perform the actions 701-705 correctly, the base station 110comprises e.g. a transmitter 830. The transmitter 830 is configured totransmit a set of parameter values, associated with a tag. Further, thetransmitter 830 is also configured to transmit a command comprising acommand tag associated with the set of parameter values to be appliedwithin the wireless communication system 100.

The transmitter 830 may further be configured to transmit the commandcomprising the command tag to a subset of user equipment 120 in the cell130. Such subset of user equipment 120 may be situated within a cell 130served by the base station 110. The subset of user equipment 120 maycomprise e.g. all user equipment 120 in idle mode, or all user equipment120 in connected mode, just to mention some non-limiting examples.

Further, the transmitter 830 may also be configured to transmit theparameter values whose values in the second set differ from the valuesof the parameters transmitted in the first set.

The transmitter 830 may in addition also be configured to transmit atime or a time delay, indicating when the set of parameter valuesassociated with a tag corresponding to the command tag is to be appliedby the user equipment 120, after having received the command.

The command comprising the command tag to be transmitted by thetransmitter 830 may be comprised in one of: a System Information Block(SIB), a Master Information Block (MIB), a paging message, a MediumAccess Control (MAC) control message, a Radio Resource Control (RRC)control message, or a message on a Physical Downlink Control Channel(PDCCH), according to different embodiments.

The transmitter 830 may be further configured to transmit aconfiguration message, comprising information concerning how tointerpret at least one code point in a set of bits transmitted in MIB,according to some embodiments. In addition, the transmitter 830 may befurther configured to transmit a set of bits in MIB comprising thecommand tag, according to the information in the configuration message.

The transmitter 830 may further be configured to inform the userequipment 120 at which period in time to read the command tag, accordingto some embodiments.

The base station 110 may in addition comprise e.g. a receiver 810. Thereceiver 810 may be configured to receive signalling from user equipment120.

Further, the base station 110 may further comprise a processing circuit820 that may be configured to process or assist in processing at leastsome of the above described actions 701-705 in order to set values ofsystem parameters utilized within a wireless communication system 100,according to some embodiments.

The processing circuit 820 may be represented by e.g. a CentralProcessing Unit (CPU), a microprocessor, or other processing logic thatmay interpret and execute instructions. The processing circuit 820 mayperform data processing functions for inputting, outputting, andprocessing of data including data buffering and device controlfunctions, such as call processing control, user interface control, orthe like.

It is to be noted that any internal electronics of the base station 110,not completely necessary for understanding the present method accordingto actions 701-705 have been omitted from FIG. 8, for clarity reasons.

Further, it is to be noted that some of the described units 810-830comprised within the base station 110 in the wireless communicationsystem 100 are to be regarded as separate logical entities but not withnecessity separate physical entities.

The actions 701-705 in the base station 110 may be implemented throughone or more processing circuits 820 in the base station 110, togetherwith computer program code for performing the functions of the presentactions 701-705. Thus, a computer program product, comprisinginstructions for performing the actions 701-705 in the base station 110may perform those actions in order to set values of system parametersused within a wireless communication system 100, when the computerprogram product is loaded into the processing circuit 820.

The computer program product mentioned above may be provided forinstance in the form of a data carrier carrying computer program codefor performing the method actions according to the present method whenbeing loaded into the processing circuit 820. The data carrier may bee.g. computer readable storage medium such as a hard disk, a CD ROMdisc, a memory stick, a flash memory, an optical storage device, amagnetic storage device or any other appropriate medium such as a diskor tape that may hold machine readable data. The computer program codemay furthermore be provided as program code on a server and downloadedto the base station 110 remotely, e.g. over an Internet or an intranetconnection.

When using the formulation “comprise” or “comprising” it is to beinterpreted as non-limiting, i.e. meaning “consist at least of”. Thepresent methods and nodes are not limited to the above describedembodiments. Various alternatives, modifications and equivalents may beapplied. Therefore, the above embodiments are not to be taken aslimiting the scope of claimed protection, which instead is to be definedby the appending claims.

What is claimed is:
 1. A method in a user equipment, for applying avalue of a system parameter used in a cell served by a network node of awireless communication system, the method comprising: receiving multipledifferent values of the system parameter from the network node, eachvalue being associated with a distinct tag; storing the multipledifferent values and the associated tags; receiving, from the networknode, information on when to receive an indication of a value of thesystem parameter to apply in the cell; receiving from the network node,in accordance with the received information on when to receive theindication, the indication of the value of the system parameter to applyin the cell, the indication comprising a value tag associated with thevalue; applying one of the stored values of the system parameter whenthe tag associated with the stored value corresponds to the value tag ofthe indication.
 2. The method of claim 1, wherein receiving theindication further comprises determining whether the indicated value ofthe system parameter is different from a value of the system parametercurrently applied by the user equipment, and applying the indicatedvalue only when determined to be different.
 3. The method of claim 1,further comprising receiving information related to a time delay,wherein the one of the stored values is applied after the time delaycounted from the time of receiving the indication.
 4. The method ofclaim 1, wherein the indication is received in a System InformationBlock.
 5. The method of claim 1, wherein the indication of the value ofthe system parameter is received periodically.
 6. The method of claim 5,wherein a period for receiving the indication is configurable.
 7. Themethod of claim 1, further comprising receiving a value of the systemparameter from the network node when no stored value has an associatedtag corresponds to the value tag of the indication.
 8. A user equipment,configured to apply a value of a system parameter used in a cell servedby a network node of a wireless communication system, the user equipmentcomprising: a receiver circuit; a transmitter circuit; a processingcircuit operatively coupled to the receiver circuit and the transmittercircuit; and a memory operatively coupled to the processing circuit;wherein the processing circuit is configured to: receive multipledifferent values of the system parameter from the network node, via thereceiver circuit, each value being associated with a distinct tag,store, in the memory, the multiple different values and the associatedtags; receive from the network node, via the receiver, information onwhen to receive an indication of a value of the system parameter toapply in the cell; receive from the network node, in accordance with thereceived information on when to receive the indication, the indicationof the value of the system parameter to apply, the indication comprisinga value tag associated with the value; apply one of the stored values ofthe system parameter when the tag associated with the stored valuecorresponds to the value tag of the indication.
 9. A method in a networknode of a wireless communication system, for indicating a value of asystem parameter used in a cell served by the network node, the methodcomprising: transmitting multiple different values of the systemparameter to a user equipment in the cell, each value being associatedwith a distinct tag; transmitting information on when the user equipmentis to receive an indication of a value of the system parameter to applyin the cell; and transmitting, in accordance with the transmittedinformation, the indication of the value of the system parameter toapply in the cell, the indication comprising a value tag associated withthe value.
 10. The method of claim 9, further comprising transmittinginformation related to a time delay after which the indicated value isto be applied, counted from a reception time of the indication at theuser equipment.
 11. The method of claim 9, wherein the indication istransmitted in a System Information Block.
 12. The method of claim 9,wherein the indication of the value of the system parameter to apply forperforming random access in the cell is transmitted periodically. 13.The method of claim 12, wherein a period for transmitting the indicationis configurable.
 14. A network node configured for a wirelesscommunication system, and for indicating a value of a system parameterused for performing random access in a cell served by the network node,the network node comprising: a transmitter circuit; and a processingcircuit operatively coupled to the transmitter circuit and configured touse the transmitter circuit to: transmit multiple different values ofthe system parameter to a user equipment in the cell, each value beingassociated with a distinct tag; transmit information on when the userequipment is to receive an indication of a value of the system parameterto apply in the cell; and transmit, in accordance with the transmittedinformation, the indication of the value of the system parameter toapply in the cell, the indication comprising a value tag associated withthe value.